1. Field of the Invention
This invention relates to a method and system for the passive determination of the range and type of a target.
2. Description of the Related Art
A passive infrared search and track (IRST) system is described in U.S. Pat. No. 4,221,966 issued Sep. 9, 1980 to Kerr et al. These IRST systems used to detect and track airborne targets currently lack the capability to provide operationally useful estimates of target range and/or velocity. Providing this capability would be a significant enhancement to the performance of the IRST, and ultimately, the naval combat system in the self-defence of the ship. An effective ranging function could help alleviate the difficult target/clutter discrimination problem all IRST systems encounter, permitting potentially quicker and more reliable target designation and prioritization. Potential advantages to the naval combat system include:
(a) An increase in the combat system effectiveness against fast sea-skimming Anti-Ship Missiles (ASM) especially if the ASM deploys electronic countermeasures to disrupt tracking radar or are passive. PA0 (b) Improvement in the ship defence capability in emission controlled (EMCON) conditions when active ranging methods may alert or direct the threat to the ship. PA0 (c) An enhanced Threat Evaluation and Weapon Assignment (TEWA) process that is less vulnerable to hostile electronic counter-measures